The present invention relates to a transmission gear wheel, and more particularly, a transmission gear wheel comprising two gear wheel elements provided with teeth on a circumference thereof and which, coaxially and non-displaceably with respect to one another in a circumferential direction and by way of mutually offset teeth are operatively connected such that, for engagement of a meshing gear wheel, existing tooth flank play is one of reduced and discontinued.
A conventional method for reducing the tooth flank play in the case of meshing gear wheels to construct one gear wheel such that tooth flanks of one line of teeth engage with the meshing gear wheel in short succession. For this purpose, one wheel of a pair of mutually meshing gear wheels consists of two gear rings of which one takes over the torque transmission and the other takes over the compensation of the play and which are prestressed with respect to one another in the circumferential direction by a spring as described in German Registered Utility Model 74 00 276.
Furthermore, U.S. Pat. No. 1,746,178 describes a gear wheel with two toothed disks of the same toothing which are arranged slightly offset with respect to one another. Both toothed disks are adjustably but fixedly connected with one another. This gear wheel is used for permitting the adjustment of the tooth flank play with the meshing gear wheel by an offsetting of the two gear disks with respect to one another. In this manner, for example, wear can be compensated by adjusting the toothed disks.
An object of the present invention is to provide a gear wheel made of two gear wheel elements which are firmly connected with one another while additionally, independently of wear, damping the noise generated during the interaction of meshing gear wheels.
According to the present invention, the foregoing object has been achieved by providing that at least the teeth of one of the gear wheel elements are deformable due to a selected elasticity such that, during the engagement of the meshing gear wheel, at least starting at a defined transmitted torque, an offset in the circumferential direction of a torque transmitting tooth is at least partially discontinued with respect to a corresponding tooth of the other gear wheel elements via a deformation.
The teeth of at least one gear wheel element, with respect to their elasticity, are such that, during the engagement of the meshing gear wheel (at least starting at a defined transmitted torque), offsetting in the circumferential direction of the tooth transmitting this torque with respect to the tooth of the other gear wheel element is at least partially discontinued.
This implementation advantageously results in a very good reduction of noise which prevents a so-called gear wheel clattering. In addition, the originally existing tooth flank play is reestablished under load, and both gear wheel elements are advantageously used for the torque transmission with the meshing gear wheel although they are fixedly and non-displaceably in a mutually offset manner connected with one another.
The present invention has a number of advantages. First, at least one gear wheel element is made of metal and/or a sintered material, the resistance to wear will be good. Second, if the two gear wheel elements have the same tooth shape, they can easily be manufactured together. If, during their mounting, these elements are then offset with respect to one another on the reference diameter by approximately 1/10 mm coaxially and nondisplaceably with respect to one another in the circumferential direction, the noise generated during the meshing with the engaging gear wheel is optimally reduced.
It is further advantageous for the engagement with the meshing gear wheel for both gear wheel elements to have the same outside diameter and for the gear wheel element with the deforming teeth to have a smaller root diameter This is also advantageous for the forces occurring during the deformation and with respect to the wear.
The present invention provides easy manufacturability of the gear wheel element with the deforming teeth and the above-mentioned characteristics if, centrally in the tooth spaces, the element has notches in the radial direction corresponding to the spacing of the teeth
The gear wheel of the present invention can be manufactured at reasonable cost if it is constructed as a plane toothed disk. The manufacture of such a toothed disk of a metal sheet made spring steel is, in turn, favorable for the force ratio and wear during torque transmission.
The firm connection between the two gear wheel elements can be established in a simple manner by screws. For reasons of space in the transmission housing, the present invention provides further advantages by constructing the gear wheel element with the deforming teeth to be constructed as a toothed disk which is indented in a plate shape. As viewed in the axial direction, the root circle and the tip circle of the teeth will then be offset with respect to one another. This offset characteristic also has an advantageous effect on the power transmission.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.